1// SPDX-License-Identifier: GPL-2.0
2/*
3 * IA-64 Huge TLB Page Support for Kernel.
4 *
5 * Copyright (C) 2002-2004 Rohit Seth <rohit.seth@intel.com>
6 * Copyright (C) 2003-2004 Ken Chen <kenneth.w.chen@intel.com>
7 *
8 * Sep, 2003: add numa support
9 * Feb, 2004: dynamic hugetlb page size via boot parameter
10 */
11
12#include <linux/init.h>
13#include <linux/fs.h>
14#include <linux/mm.h>
15#include <linux/hugetlb.h>
16#include <linux/pagemap.h>
17#include <linux/module.h>
18#include <linux/sysctl.h>
19#include <linux/log2.h>
20#include <asm/mman.h>
21#include <asm/tlb.h>
22#include <asm/tlbflush.h>
23
24unsigned int hpage_shift = HPAGE_SHIFT_DEFAULT;
25EXPORT_SYMBOL(hpage_shift);
26
27pte_t *
28huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
29{
30	unsigned long taddr = htlbpage_to_page(addr);
31	pgd_t *pgd;
32	p4d_t *p4d;
33	pud_t *pud;
34	pmd_t *pmd;
35	pte_t *pte = NULL;
36
37	pgd = pgd_offset(mm, taddr);
38	p4d = p4d_offset(pgd, taddr);
39	pud = pud_alloc(mm, p4d, taddr);
40	if (pud) {
41		pmd = pmd_alloc(mm, pud, taddr);
42		if (pmd)
43			pte = pte_alloc_map(mm, pmd, taddr);
44	}
45	return pte;
46}
47
48pte_t *
49huge_pte_offset (struct mm_struct *mm, unsigned long addr, unsigned long sz)
50{
51	unsigned long taddr = htlbpage_to_page(addr);
52	pgd_t *pgd;
53	p4d_t *p4d;
54	pud_t *pud;
55	pmd_t *pmd;
56	pte_t *pte = NULL;
57
58	pgd = pgd_offset(mm, taddr);
59	if (pgd_present(*pgd)) {
60		p4d = p4d_offset(pgd, taddr);
61		if (p4d_present(*p4d)) {
62			pud = pud_offset(p4d, taddr);
63			if (pud_present(*pud)) {
64				pmd = pmd_offset(pud, taddr);
65				if (pmd_present(*pmd))
66					pte = pte_offset_map(pmd, taddr);
67			}
68		}
69	}
70
71	return pte;
72}
73
74#define mk_pte_huge(entry) { pte_val(entry) |= _PAGE_P; }
75
76/*
77 * Don't actually need to do any preparation, but need to make sure
78 * the address is in the right region.
79 */
80int prepare_hugepage_range(struct file *file,
81			unsigned long addr, unsigned long len)
82{
83	if (len & ~HPAGE_MASK)
84		return -EINVAL;
85	if (addr & ~HPAGE_MASK)
86		return -EINVAL;
87	if (REGION_NUMBER(addr) != RGN_HPAGE)
88		return -EINVAL;
89
90	return 0;
91}
92
93struct page *follow_huge_addr(struct mm_struct *mm, unsigned long addr, int write)
94{
95	struct page *page;
96	pte_t *ptep;
97
98	if (REGION_NUMBER(addr) != RGN_HPAGE)
99		return ERR_PTR(-EINVAL);
100
101	ptep = huge_pte_offset(mm, addr, HPAGE_SIZE);
102	if (!ptep || pte_none(*ptep))
103		return NULL;
104	page = pte_page(*ptep);
105	page += ((addr & ~HPAGE_MASK) >> PAGE_SHIFT);
106	return page;
107}
108int pmd_huge(pmd_t pmd)
109{
110	return 0;
111}
112
113int pud_huge(pud_t pud)
114{
115	return 0;
116}
117
118void hugetlb_free_pgd_range(struct mmu_gather *tlb,
119			unsigned long addr, unsigned long end,
120			unsigned long floor, unsigned long ceiling)
121{
122	/*
123	 * This is called to free hugetlb page tables.
124	 *
125	 * The offset of these addresses from the base of the hugetlb
126	 * region must be scaled down by HPAGE_SIZE/PAGE_SIZE so that
127	 * the standard free_pgd_range will free the right page tables.
128	 *
129	 * If floor and ceiling are also in the hugetlb region, they
130	 * must likewise be scaled down; but if outside, left unchanged.
131	 */
132
133	addr = htlbpage_to_page(addr);
134	end  = htlbpage_to_page(end);
135	if (REGION_NUMBER(floor) == RGN_HPAGE)
136		floor = htlbpage_to_page(floor);
137	if (REGION_NUMBER(ceiling) == RGN_HPAGE)
138		ceiling = htlbpage_to_page(ceiling);
139
140	free_pgd_range(tlb, addr, end, floor, ceiling);
141}
142
143unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
144		unsigned long pgoff, unsigned long flags)
145{
146	struct vm_unmapped_area_info info;
147
148	if (len > RGN_MAP_LIMIT)
149		return -ENOMEM;
150	if (len & ~HPAGE_MASK)
151		return -EINVAL;
152
153	/* Handle MAP_FIXED */
154	if (flags & MAP_FIXED) {
155		if (prepare_hugepage_range(file, addr, len))
156			return -EINVAL;
157		return addr;
158	}
159
160	/* This code assumes that RGN_HPAGE != 0. */
161	if ((REGION_NUMBER(addr) != RGN_HPAGE) || (addr & (HPAGE_SIZE - 1)))
162		addr = HPAGE_REGION_BASE;
163
164	info.flags = 0;
165	info.length = len;
166	info.low_limit = addr;
167	info.high_limit = HPAGE_REGION_BASE + RGN_MAP_LIMIT;
168	info.align_mask = PAGE_MASK & (HPAGE_SIZE - 1);
169	info.align_offset = 0;
170	return vm_unmapped_area(&info);
171}
172
173static int __init hugetlb_setup_sz(char *str)
174{
175	u64 tr_pages;
176	unsigned long long size;
177
178	if (ia64_pal_vm_page_size(&tr_pages, NULL) != 0)
179		/*
180		 * shouldn't happen, but just in case.
181		 */
182		tr_pages = 0x15557000UL;
183
184	size = memparse(str, &str);
185	if (*str || !is_power_of_2(size) || !(tr_pages & size) ||
186		size <= PAGE_SIZE ||
187		size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
188		printk(KERN_WARNING "Invalid huge page size specified\n");
189		return 1;
190	}
191
192	hpage_shift = __ffs(size);
193	/*
194	 * boot cpu already executed ia64_mmu_init, and has HPAGE_SHIFT_DEFAULT
195	 * override here with new page shift.
196	 */
197	ia64_set_rr(HPAGE_REGION_BASE, hpage_shift << 2);
198	return 0;
199}
200early_param("hugepagesz", hugetlb_setup_sz);
201